Integrated circuits are being given higher and higher numbers of terminals and are thereby continuing to be miniaturized further. The difficulties with the application of solder paste and with equipping to be anticipated given this increasing miniaturization are to be overcome by new housing forms, whereby single, few or multi chip modules in a ball grid array package are to be particularly emphasized here (German periodical, productornic 5, 1994, pages 54, 55). These modules are based on a through-contacted substrate on which the chips are contacted, for example, via contacting wires or with flip-chip mounting. The ball grid array (BGA), which is often also referred to as solder grid array, land grid array or solder bump array, is situated at the underside of the substrate. At the underside of the substrate, the ball grid array comprises planarly arranged solder bumps that enable a surface mounting on the printed circuit boards or assemblies. High numbers of terminals in a rough grid of, for example, 1.27 mm can be realized as a result of the planar arrangement of the solder bumps.
Injection molded parts with integrated interconnections are employed instead of conventional printed circuits in what is referred to as MID technology (MID=Moulded Interconnection Devices). High-grade thermoplastics that are suitable for the injection molding of three-dimensional substrates are the basis of this technology. Such thermoplastics are distinguished over traditional substrate materials for printed circuits by better mechanical, thermal, chemical, electrical and environmental properties. In a specific direction of MID technology, what is referred to as SIL technology (SIL=Spritzgiessteile mit integrierten Leiterzugen injection molded parts with integrated interconnections!), the structuring of a metal layer applied onto the injection molded parts ensues with a specific laser structuring method, foregoing the otherwise standard mask technique. A number of mechanical and electrical functions can thereby be integrated into the three-dimensional injection molded parts with structured metallization. The housing carrier function simultaneously assumes guides and snap-in connections, whereas the metallization layer, in addition to the wiring and connecting function, also serves as electromagnetic shielding and sees to a good heat elimination. Further details about the manufacture of three-dimensional injection molded parts with integrated connector trains derive, for example, from German Patent DE-A- 37 32 249 or European Patent EP-A-0 361 192.
U.S. Pat. No. 5,081,520 discloses a method for fastening IC chips on substrates wherein the substrates are produced as injection molded parts with integrated bumps for the fastening of the IC chips. A connecting layer is applied after the metallization, so that the IC chips can be secured to the substrates, whereby the chip terminal surfaces are electrically conductively connected to the allocated metallizations of the bumps.